[PATCH RFC] dt-bindings: pinctrl: support specifying pins

[Rafał Miłecki <zajec5@xxxxxxxxx>]

From: Rafał Miłecki <rafal@xxxxxxxxxx>

Add support for "pins" node with pin@ subnodes. This allows specifying
all pins (and their names) at DT level.

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
While working with pinctrl in Linux I started wondering if we could
start specifying pins in DT instead of Linux drivers. When working with
DT we usually avoid hardcoding hardware description in drivers so it
isn't clear to me why it doesn't apply to pins.

Please let me know if this makes sense. If by some chance I'm correct I
think that specifying groups and functions could follow too.

FWIW: I didn't start working on Linux reading pins from DT yet.
---
 .../bindings/pinctrl/brcm,ns-pinmux.yaml      | 12 +++++++++-
 .../devicetree/bindings/pinctrl/pinctrl.yaml  | 23 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/pinctrl/brcm,ns-pinmux.yaml b/Documentation/devicetree/bindings/pinctrl/brcm,ns-pinmux.yaml
index 8d1e5b1cdd5f..92a86b0822d6 100644
--- a/Documentation/devicetree/bindings/pinctrl/brcm,ns-pinmux.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/brcm,ns-pinmux.yaml
@@ -74,7 +74,7 @@ required:
   - reg
   - reg-names
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |
@@ -83,6 +83,16 @@ examples:
         reg = <0x1800c1c0 0x24>;
         reg-names = "cru_gpio_control";
 
+        pins {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            pin@0 {
+                reg = <0>;
+                label = "spi_clk";
+            };
+        };
+
         spi-pins {
             function = "spi";
             groups = "spi_grp";
diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/pinctrl.yaml
index d471563119a9..d2f105e9570d 100644
--- a/Documentation/devicetree/bindings/pinctrl/pinctrl.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/pinctrl.yaml
@@ -42,4 +42,27 @@ properties:
       This property can be set either globally for the pin controller or in
       child nodes for individual pin group control.
 
+  pins:
+    type: object
+    properties:
+      '#address-cells':
+        const: 1
+
+      '#size-cells':
+        const: 0
+
+    patternProperties:
+      "^pin@[0-9a-z]+$":
+        type: object
+
+        properties:
+          reg:
+            description: Pin number
+
+          label:
+            description: Pin name
+            $ref: /schemas/types.yaml#/definitions/string
+
+        additionalProperties: false
+
 additionalProperties: true
-- 
2.31.1